Work-clamping mechanism for sewing-machines



E. B. ALL EN. WORK CLAMPING MECHANISM FOR SEWINI MACHINES. APPLICATIONFILED OCT- 20, I9I5- RENEWED SEPT. I7, 1918- 1,379,894. Patented May31,1921;

2 SHEETS-SHEET WINES-86$: 0%. 91M

P E. B. ALLEN. WORK CLAMPING MECHANISM FOR SEWING MACHINES;

APPLICATION FILED OCT, 20, 1915- REN EWED SEPT. 17,1918. 1,379,894.

Patented May 31, 1921.

2 SHEETS-SHEET 2.

INVENTOR EDWARD IB. ALLEN; OF BRIDGEPOBT, CONNECTICUT, ASSIGNOR TO THESINGER MANN- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.

WORK-CLAMPING MECHANISM non SEWING-MACHINES.

T 0 all w liom it may concern:

Be it known that I, EDWARD B; ALLEN, a

citizen of the United States, residing at' Bridgeport, in the county ofF airfield and State of Connecticut, have invented certain new anduseful Improvements in W'ork- Clamping Mechanisms for Sewing-Machines,of which the following is a spec1fication, reference being had thereinto the accompanying drawings.

The present invention has for its ob ects to simplify and effect thepositive control of the clamp-closing means and to secure therefor amore advantageous timing relative to the operative movements of thecuttlng device.

In the preferred form of the present 1mprovement, the cutting devicecomprises a traveling fulcrum-pin upon which are mounted thecutter-carrying rocklevers actuated by separate cams upon the transversecutter-shaft, the fulcrum-pin being mounted upon a slide-block derivingoperative movements from an adjustable connection with another cam uponthe cutter-shaft. The clamp-operating cam-shaft upon one of thelaterally separable sections of the workclamp has the usual lateraltappet-arm which is engaged by the forward extremity of theclamp-closing rock-lever mounted upon a fixed fulcrum and havingintermediate its fulcrum and its outer end an arched cam-slot which isentered by a stud carried by the lower cutter-lever.

In the travel of the cutting device between retracted and cuttingpositions the substantially rectilinear advance of the stud with thelower cutter-lever through the initial inclined limb of the cam-slotcauses the descent of the clamp-closing rock-lever for engagement withthe tappet-arm of the clamp-operating rock-shaft just after the forwardend of the lower cutting element moves beneath the adjacent end of theworkclamping foot. As the cutting device continues its advance to cutting position, the movement of the stud in. the forward and reverselyinclined portion of the arched cam-slot causes the rise of theclamp-closing rock-lever to afford ample clearance between its operativeend and the tap'p'et-arm, in order that the final rocking of the lowercutter-carrying lever Specification of Letters Patent. Patented May31,1921, Application filed October 20, 1915, Serial No. 56,849. RenewedSeptember 17, 1918.

Serial No. 254,512.

in the cutting action may not carry the While the traveling cuttingdevice'is preferably employed in the actuation of the clamp-closingrock-lever in a machine employing this type of device for producing thebuttonhole slit, ciprocating member performing an operative movementpreparatory to the buttonhole cutting operation maybe employed inproducing the described result. It is also evident that the mechanism asabove deit is evident that any rescribed may be modified in otherparticulars within the scope of the present invention.

In the drawings, Figure 1 is a side elevation of the lower portion of abuttonhole sewing machine embodying the present improvement, and Fig.2is a plan of the same. Figs. 3 and f are views similar to Fig. 1,

with the omission of certain parts below the top of the bed of themachine, representing the cutting device and the clamp-closing means indifferent positions.

As represented in the drawings the frame of the machine includes thehollow rectanguiarbase -1 having a suitably apertured top forming thebed-plate 2. The base is shown provided with the removable forwardsection 3 for access to the looper mechanism cooperating with areciprocating and laterally jogging thread-carrying needle 4 sustainedabove the bed-plate. The stitch-forming mechanism, as thus constituted,is or may be constructed and operated as represented in my United StatesPatent No. 1,030,046, of June 18, 1912, but its specific character isnot material to the present improvement.

Suitably journaled in the base is the longitudinally extendingmain-shaft 5 formed with qua-rtering cranks 6 embraced by the lower endsof pitman-rods '7 by'mea-ns of which it is connected with the upperneedleactuating shaft. The main-shaft 5 carries the cam-cylinder 8having the peripheral cam-groove 9 entered by a roller-stud upon an armof the rocker 1O fulcrumed beneath the bed-plate.

The rocker 10 is connected by means of the pitman 11 with theclutch-lever 12 which actuates the clutch-dogs l3 embracing a dependingflange of the feed-wheel 14. The

feed-wheel is shown provided in its upper face with the usualfeedingcam-groove 1 and side-shift cam-groove 16. The camgroove 15 is enteredby the roller-stud 17 depending from the swinging arm 18 fulcrumed at 19and provided with the longitudinally adjustable stud 20 entering atransverse slot 21 in the Work-clamp slide-plate 22. The cam groove 16is entered by a stud depending from the rock-lever 23 havinga slidingand pivotal connection with the usual cross slide-plate mounted forendwise movement upon the slide-plate 22 in a manner well known.

The slide-plate 22 sustains the edgewise and reciprocally movableclamp-plates 24 and 25 affording the lower clamping members of thework-holder. ,Each of these clamp-plates has adjustably secured thereona bearing bracket 26 sustaining near its foot the fulcrum-pin 27 of oneof the upper forwardly extending clamp-arms 28 carrying the pivoted foot29 constituting one of the upper clamping members. Journaled in thebearing bracket 26 above the adjacent portion of the clamp-arm 28 is thetransverse clamp-operating rock-shaft 30 provided upon one side with thecam projection 31 adapted for engagement with the clamp-arm for pressingthe same downward to close the clamp in opposition to the lifting spring32.

The rock-shafts 30 are in the present construction made separate toenable the separable sections of the clamp to be shifted relatively andthey are coupled together when in operative position by means of acrank-arm 33 fixed upon the one and provided with a lateral pin 34entering a fork 35 in a similar crank-arm 36 fixed upon the other ofsaid rock-shafts. The rock-shaft 30 at the right, as seen from the frontend of the machine, is provided with a laterally extending benttappet-arm 37 and with an upwardly extending tappet-arm 38 by means ofwhich the shaft may be rocked in opposite directions for closing andopening the clamp. The said rock-shaft is also provided with thefinger-lever 39 by means of which the clamp may be manually operated themovements of one rock-shaft being communicated to the other by theconnection before described.

Suitably journaled in the frame slightly above the bed-plate 2 is thetransverse cutter-shaft 40 provided upon one end with the loose groovedbelt-wheel 41 derivingcon- 5 .This clutch tinuous rotary motion from abelt leading from the source of power independently of the main-shaft 5.Between the hub 42 of the belt-wheel 41 and the disk 43 fixed upon theshaft 40 is a clutch device controlled by means of the flange 44 of thecontrolling lever 45 fulcrumed at 46 and pressed normally intoclutch-disengaging position by means of the spring 47 interposed betweenthe flange 44 and the boss 48 rising from the bed-plate 2. deviceoperates to control the connection of the cutter-shaft with its drivingmeans in such manner that the shaft performs a single rotation onlypreparatory to each buttonhole stitching operation.

The cutter mechanism represented in the drawings is substantially thatof my Patent No. 1,048,786. It comprises a traveling fulcrum-blockhaving spaced parallel flanges 49 between which are pivotally mounted bymeans of the fulcrum-pin 50 the upper and lower cutter-carrying levers51 and 52. The upper lever 51 carries the cutting knife 53 and the lowerlever carries the cooperating block 54. The fulcrum-carrying slide-blockis fitted within a suitable slideway of the bed-plate.

The rearward ends of the cutter-levers are drawn together by means of aspring 55 which maintains the fiat adjacent edges of I the cutter-leverspermanently in contact or operative relation with their respectiveactuating cams 56 and 57 fixed upon the cutter-shaft 40. Thecutter-shaft has also secured thereon the cam-disk 58 formed in one facewith the cam-groove 59 entered by the lateral stud 60 of the link-bar 61having at its rearward end a yoke 62 embracing the cutter-shaft and itsforward end apertured to receive the stud-bolt 63 projecting laterallyfrom the rearward extension of one of the fulcrum-sustaining flanges 49,whereby the fulcrum-block and the cutter-levers are given travelingmovements toward and from stitching position preparatory and subsequentto each buttonhole cutting operation. The cutting device thus performsbut a single reciprocatory traveling movement for each. feeding cyclemeasured by a rotation of the feed-wheel.

Secured upon the bed-plate 2 is a bearing bracket 65 carrying thefulcrum-stud (36 upon which is pivotally mounted the clampclosingrock-lever 67 with its laterally offset and depending rounded forwardend 68 disposed normally above the tappet-arm 37 in the initial positionof the work-clamp.

Between its laterally offset forward portion and its fulcrum point theclamp-closing rock-lever is formed with an arched camslot comprising thesubstantially horizontal portion 69., and adjacent upwardly andforwardly inclined portion 70 and a forwardly and downwardly inclinedportion 71. This cam-slot is entered by the lateral stud 72 projectingfrom the front face of the lower cutter-lever 52, and preferablyprovided with an anti-friction roller 73 upon the portion embraced bythe cam-slot.

Then the cutting device is in its normally retracted position, the stud72 occupies a position within the portion 69 of'the camslot, asrepresented in Fig. l. In-the initial travel of the cutting device tocutting position under the action ofthe cam 58 and link-bar 61, the stud'72 traverses the camslot portion 70 and imparts a full operativedownward stroke to the rock-lever 67 68, and by its'engagement with thetappet-arm 37 depresses the clamping feet 29 upon the work while thecutting elements continue their movement to cutting position in registerwith the clamping feet.

In the continued advance of the cutting device, the stud 72 traversesthe .camslot portion 71 and thereby lifts the rock-lever 67 68 clear ofthe tappet-arm 37, so that in the final closing movement of the cuttingelements the descent of the stud 72 in the rocking movement of the lowercutter-lever 52 will not impart to the clamp-closing rock-lever a dipsufficient to cause a reengagement of the rock-lever with the tappet 37with such force as to turn the rock-shaft 3O appreciably beyond itsnormal clampclosing position or to injure the parts.

In the return of the cutting device to initial retracted position, therock-lever 67 68 obviously receives movements correspondwith thosedescribed but in the reverse order, and without affecting the positionof the work-clamp which remains closed by reason of the positioning ofthe cam projection 31 beyond the center of the rockshaft 30.

The horizontal cam-slot portion 69 is designed to afford clearance forthe stud 72 in the adjustment of the connection 63 between the link-bar61 and the fulcrum-carrying block in order to properly locate thecutting position relatively to the work-clamp for different cuttingelements which the cutterlevers are designed to accommodateinterchangeably. The clamp-closing rock-lever and its cam-slot arepreferably so shaped and positioned with relation to the stu'd72 thatthe closing movement of the clamp is not commenced until the lowercutting element or lCDlfG-blOCk has advanced sufliciently to lie beneaththe adjacent ends of the clamping feet so as to avoid the collision oftheir adjacent extremities and consequent injury of the parts.

As described more fully in my said application, the top of the bed-plateis longitudinally channeled to receive the slide-bar 74 from which risesthe post 75 carrying the adjustably mounted clampopening tripping pin 76adapted for engagement with the tappct-arm 38 of the clamp-operatingrockshaft 30. The slide-bar 74 is connected by a link '77 with thelaterally extending arm 7 8 fixed. upon a rocking pin 79 extendingthrough the bed-plate and carrying upon its lower end the arm 80normally lying in'the path of movement of the cam projection 81 uponthe-feed cam-wheel 14, the arm '80 rest-' ing normally upon theperiphery of the latter by the action of the spring 82 connecting andthe clamp closing rock-lever; while the said rock-lever is positivelycontrolled and is not dependent upon a spring whose disconnection orbreakage would permit the rock lever to assume a position during thetravel of the work-clamp which ,would cause a collision likely todisarrange or injure the parts involved. 7

Although in the embodiment of the present improvement represented in theaccoanpanying drawings the connection between the reciprocatorycutter-carrying member and the clamp-closingrock-lever is in the form'ofa cam-track and a follower-stud engaging the same, it is obvious thatthe present invention includes within its scope any other suitable meansfor converting the substantially rectilinear reciprocatory movement ofthe one into a tilting o-r vibratory movement of the other. I

Having thus set forth the nature of the invention, what I claim hereinis 1. In a buttonhole sewing machine, the combination withstitch-forming mechanism, a work-clamp, and means for producing betweenthe same relative feeding.

movements, of clamp closing means includmg a rock-lever mountedindependently of and adapted for engagement with an element of thework-clamp, an actuating membervperforining a complete bodilyreciprocation relatively to and lengthwise of said rock-lever once onlyfor each feeding cycle, and an operative connection between saidactuating member and the rock-lever for imparting to the latter itsoperative movements. 7

2. In a buttonhole sewing machine, the combination with stitch-formingmechanism and a work-clamp, of clamp-closing means including arock-lever, a fixed fulcrum therefor, a reciprocatory actuating member,and an operative connection between said rock-lever and actuating membercomprising a cam element upon the one and a follower thereior upon theother.

3. In a buttonhole sewing machine, the combination with stitch-formingmechanism and a work-clamp, of clamp-closing means including arock-lever having a camtrack, fixedl ulcrum for said rock-lever and areciprocatory actuating member, and a stud carried thereby in operativeengagement with said cam-track of the rock-lever.

l. in a buttonhole sewing machine, the combination with stitch-formingmechanism and a worloclamp, of clamp-closing means including a rockingand reciprocating actuating member, a stud carried thereby, and arock-lever having a cam element adapted for operative engagement by saidstud and shaped to eftect a to-and-fro rocking movement of said lever inthe travel of said member preparatory to its rocking movement.

5. In a buttonhole sewing machine, the

combination with stitch-forming mechanisin, a work-clamp, and a bodilytraveling buttonhole cutting device having cutting elements movable intoand out of register with the work-holder, of clamp-closing meanscomprising a rock-lever mounted independently of the work-clamp andrelative to which rock-lever said cutting device performs its travelingmovements, and. an operative connection between the cutting device andsaid. rock-lever including a cam element upon the one and a followerthere for upon the other.

6. In a buttonhole sewing machine, the combination with stitch-formingmechanism, a work-clamp, and a buttonhole cut ting device comprising twocarriers, cooperating cutting elements mounted respectively upon saidcarriers, a pivotal connection between said carriers, and means forimparting to said carriers bodily traveling movements toward and fromthe workclamp and relative rocking movements upon said pivotalconnection, of clamp-closing means comprising a rock-lever mountedindependently of said wont-clamp and relative to which rock-lever saidcarriers perform their traveling movements, and an operative connectionbetween the rock-lever and one of said carriers including a cam elementupon the one and a follower upon the other.

7. In a buttonhole sewing machine, the combination with stitch-formingmechanism, a work-clamp, and a buttonhole cutting device comprising twocarriers, cooperating cutting elements mounted respectively upon saidcarriers, a pivotal connection between said carriers, and means forimparting to said carriers traveling movements toward and from thework-clamp and relative rocking movements upon said pivevasea otalconnection, of clamp-closing means comprising a rock-lever formed with acamtraclr inclined to the direction of traveling movement of the cuttingdevice, and a stud sustained by one of said carriers and engagingsaidcam-track to produce a rocking movement of said lever.

8. ln buttonhole'sewing machine, the combination with stitch-formingmechanism, a work-clamp, and a buttonhole cu: ting device comprisingupper and lower cutting levers, cooperating cutting elements mountedrespectively upon said levers, a "fulcrum-stud upon which said leversare mounted, means for imparting to said fulcrum-stud travelingmovements toward and from the work-clamp, and means for imparting tosaid levers reciprocal rocking movements upon said fulcrum-stud, or aworn-holder comprising an upper clamping member and a controllingrock-shaft therefor provided with a tappet-arm, a rocklevermountedindependently of the workclamp and adapted for engagement with saidtappet-arm and an operative connection between the lower cutter-leverand the rock-lever comprising a cam element upon the one and a followertherefor upon the other from which the rock-lever derives operativeclamp-closing movements.

9. in a buttonhole sewing machine, the combination, with stitch-formingmechanism and a work-clamp, of elamp-closing means including arock-lever, an actuating member and means for imparting to itreciprocatory movements substantially length wise of said roclolever,and an operative connection between and sustained by said rock-lever andactuating member for closing the work-clamp into gripping relation withthe work during a bodily traveling movement of said actuating member.

10. In a buttonhole sewing machine, a frame, a work-clamp and travelingbuttonhole cutter-levers movable relatively to said frame, aclamp-closing lever :r'ulcrumed on said frame, and means carried by oneof said cutter-levers and acting upon said clamp-closing lever to closethe work-clamp into gripping relation with the work during the travel ofsaid cutter-levers to cutting position.

11. In a buttonhole sewing machine, a frame, a work-clamp and travelingbuttonhole cutter-levers movable relatively to said frame, aclamp-closing lever fulcrumed at one end to said frame and having itsother end disposed in operative relation with an element 0:6 theworloclamp, and an operative connection between one of said cutterleversand a point on said clamp-closing lever intermediate the ends of thelatter.

12. lln a buttonhole sewing machine, in combination, a work-clamp,buttonhole cutting mechanism including traveling cutterpoint, buttonholecutting mechanism in-' cluding a cutter carrying element and anoperative connection for transmitting power from said element to saidclamp-closing lever.

14. In a buttonhole sewing machine, a

stationary frame, a traveling work-clamp sustained by said frame, aclamp-closing lever pivoted to a stationary part of the frame,buttonhole-cutting mechanism including a traveling cutter, and anoperative connection for transmitting power from said traveling cutterto said clamp-closing lever.

15. In a buttonhole sewing machine, a stationary frame, a travelingwork-clamp sustained thereby, a buttonhole cutter, a cutter-operatingshaft, a clamp-closing lever fulcrumed on said frame, and a cam operatedconnection distinct from said cutter-operating shaft between saidbuttonhole cutter and clamp-closing lever.

16. In a buttonhole sewing machine, a work-clamp, a clamp-closing lever,an actuating device mounted for reciprocation in a direction lengthwiseof said lever, and an operative connection between said lever andactuating device comprising a cam and c0- operative member, said camextending mainly in a. direction lengthwise of said lever but having aside throw sufiicient to rock the clamp-closing lever and close theClamp.

17. In a buttonhole sewing machine, a I

stationary frame, a traveling work-clamp sustained by said frame,buttonhole cutting mechanism including a cutting lever, a clamp-closinglever fulcrumed at one end to said frame, and a connection. fortransmitting power from said cutter-lever to said clamp-closing lever.

In testimony whereof, I have signed my name to this specification,in thepresence of two subscribing witnesses.

EDWARD B. ALLEN. Witnesses:

STANLEY N. SMITH, HENRY J. MILLER.

